We read 11 results from Los Alamos Municipal Water System’s 2021 water quality report. No results over a legal limit; 3 above a health goal or guideline.
Serves about 25,000 people · Water system ID NM3500115 · Read the district’s 2021 report (opens in a new tab)
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Results from the 2021 report
Each number is copied from the district’s report and links to the page it’s printed on. Where the report lists several plants, wells or purchased water, the highest is shown.
| Contaminant | Result | Health goal | Legal limit | What it means |
|---|---|---|---|---|
| Arsenichighest measured · sampled 2023 · Wells · 2021 report, page 2 | 2.1 ppb | 0.004 ppb | 10 ppb | Above the health goal525x the health goal |
| Gross beta (radioactivity)highest measured · range 1.13 to 1.99 · sampled 2024 · Wells · 2021 report, page 2 | 1.99 pCi/L | 0 pCi/L | 50 pCi/L | Above the health goalThe health goal is zero |
| Uraniumhighest measured · range ND to 1.9 · sampled 2024 · Wells · 2021 report, page 2 | 1.9 ppb | 0.6 ppb | 30 ppb | Above the health goal3.2x the health goal |
| Bariumhighest measured · sampled 2023 · Wells · 2021 report, page 2 | 0.04 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chlorineas reported · range 0.4 to 0.5 · sampled 2025 · Distribution system · 2021 report, page 2 | 0.5 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of homes tested, 0 over the action level · sampled 2023 · Customer taps · 2021 report, page 2 | 0.03 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range ND to 1.3 · sampled 2025 · Distribution system · 2021 report, page 2 | 1.3 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 6.4 to 7.76 · sampled 2025 · Distribution system · 2021 report, page 2 | 7.76 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridehighest measured · sampled 2023 · Wells · 2021 report, page 2 | 0.21 ppm | 1 ppm | 4 ppm | Below the health goal |
| Nitrate (as N)highest measured · range 0.37 to 0.57 · sampled 2025 · Wells · 2021 report, page 2 | 0.57 ppm | 10 ppm | 10 ppm | Below the health goal |
| Hardnessas reported · sampled 2025 · Drinking water · 2021 report, page 1 | 3.16 gpg (54 ppm) | — | — | Soft |
Utility results describe the whole system, measured where water enters the pipes, not your tap. Your home’s plumbing can add lead or copper. 1 number we weren’t sure about is held back until a person checks.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in Los Alamos Municipal Water System’s water between Jan 2023 and Jul 2023. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium33.8 ppbFound in 6 of 6 samples · highest resultAbove EPA’s health reference level of 10 ppb (a guide, not a legal limit)
Source: EPA UCMR 5 occurrence data. The highest single result is shown; one high sample doesn’t mean every glass is that high.
What you can do
Nothing here is an emergency notice: if the district has a violation, it must tell customers directly. If you’d like to lower these at your tap, these are the treatments that remove them, and the catalog shows the models certified for each. Ranking is by certified removal; commissions never change the order.
Radium and uranium
Found: Gross beta (radioactivity), Uranium
What removes it: Reverse osmosis.
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